Method of heating



y 1936- c. A. DUNHAM ET AL 2,046,813

METHOD OF HEAT ING Filed July 8, 1929 Patented July 7, 1936 i UNITED STATES PATENT OFFICE METHOD OF HEATING Clayton A. Dunham and Aubra R. Dunham, Glcncoe,'lll., assignors to Experimental Laboratories Incorporated, Chicago, 11]., a corporation of Illinois Application July 8, 1929, Serial No. 376,537 15 Claims. (Cl. 237-12) This invention relates to a new and improved venience and comfort at a minimum of care and method of heating in which a heating medium cost. consisting of mixed steam and products of com- Other objects and advantages of this system bustion is produced in a generator of the inwill be more apparent from 'the following deternal combustion type and transmitted to and tailed description of one approved form of ap- 5 through the radiators. paratus adapted for carrying out theprinciples According to this invention the entire system of this invention. is operated under a partial vacuum, or a sub- In the accompanying drawing:

atmospheric pressure, produced by a temperature Fig. 1 is a diagrammatic elevation, partially in controlled fan or other suction means connected vertical section, showing the principal elements 10 with the outlets of the radiators. This exhaustof the heating system. ing mechanism not only draws out and expels Fig. 2 is a vertical section through the autoto the outer atmosphere the non-condensible matic fuel control valve. gases after they have given up most of their heat Fig. 3 is an elevation, partially in vertical secin the radiators and in the preceding process of tion, of one of the radiator inlet valves.

generating steam, but also maintains a sub-at- The main features of the apparatus are a, genmospheric pressure in both the radiating syserator A for the heating medium, a radiating tem and in the generator. Steam condensed in system comprising a plurality of radiating units the radiating system is returned by gravity to 'B, an exhausting mechanism C, and an autothe generator for reconversion into steam. The altlilc fuel conttrolA valve D.k vacuum produced in the generator serves notn r may ta e avariety of forms, only to draw in nnt outer atmosphere oneot its essential characteristics being that it for combustion purposes but regulates the admisis Closed f ept for the inlets for water, sion of the gas or other fuel in accordance with fuel and combustion air, and the outlet for the of e ulate assistantstransmits;

wc inurnsreg ae y eemperaure in the enclosure to be heated and by the number the bufldm? whereby P P P ur of or the of wa ;fiipfoiitii2itiieiittiitfeiifiiii ittL2? in service. The entire sys em w in e uil ing to be heated is closed, and since the system :5 32%;: g 5 i fi suitable refrac- 39 is operated under sub-atmospheric pressure if sogewhat g g al y b; 3231 51:22:12]? fi? ii gfiz 2 :2 1 f; 3;: the Outer casing comprises a bottom wall I: m er th f om P vertical cylindrical side walls 2, and a dome us e t in ti 1 t shaped roof or cover 3 from which leads the sup- 35 prinqlpal obJec 0 ven on s 0 ply pipe 4 forconducting the heating medium to provide an improved method of heating of the the radiating system The main t type briefly described hereinabove and disclosed Inner con amer more in detail in the specifications which follow. inner and outer cylindrical walls 6 and 1 forms Another ob ect is to provide a method of heatan annular container or basin for the main 40 ing which utilizes a boiler of the internal complyvof water indicated at 8 A pan 9 open 2 bustion type operating under sub-atmospheric pressures.

Another object is to provide a method of heatwalls H is s ing designed to prevent possible leaks of gas into undrical wall the building.

7 Another object is to provide a. method in which do the fuel burned and the combustion air admitted ing filfig fiz fig gt is regulated by the radiator control, that is when form a water l, Th i 30 additional radiating space is added the combusupwardly through the bott tion will be automatically increased to provide extends centrally upward within the lower poradditional heating medium.

Another object is to provide a simple, inexthird water container or reservoir 15 of annular pensive and eflicient method of heating small form. The air inlet pipe l6 leads in through one 5 structures, which will give a maximum of conwall. I! of the building from the outer atmos- 5 her, the flame being indicated at 23. Any suitwater discharge pipe able means may be utilized to ignite the fuel. An opening closed by a removable plug 60 may be provided in the outer casing 2, through which opening a lighted taper or an electric-sparking device can be inserted to initially ignite the gas, after which plug 60 is replaced to seal the opening. A plurality of circular series of openings 24 and 25 are formed in the cylindrical wall 6 to permit the products of combustion to pass from chamber 22 into the main chamber within the outer casing. The lower openings 25 also determine the water level in the outer reservoir 8. A 26 leads from a fitting 21 in the air inlet pipe l6, pipe 26 being looped upwardly at 28 to provide a water seal against the entrance or escape of gases through this pipe.

The gas supply pipe 29 leads from the outside source of gas supply to the valve chamber 3|! of the automatic control valve D, the supply pipe |9 leading from this valve chamber to the burner 2 One suitable form of control valve D is indicated diagrammatically in Fig. 2. A valve plate 3| is adapted to engage with the valve seat 32 to cut off the fiow of gas or other fuel through the valve.

- Valve stem 33 leads upwardly from valve plate 3| v the valve against to a flexible diaphragm 34 housed in a diaphragm casing 35. The chamber 36 beneath the diaphragm 34 is open to atmospheric pressure through aperture 31. The chamber 38 above diaphragm 34 is connected through pipe 39 with the interior of generator A, whereby diaphragm chamber 38 will always be under substantially the pressure existing in the generator. A sealing diaphragm 40 of the flexible bellows type is connected between the valve casing 30 and the valve plate 3| to prevent the escape of gas around valve stem 33 in the upper portion of thevalve casing.

When the chambers 36 and 39 at the two sides of diaphragm 34 are both under atmospheric pressure and diaphragm 34 isin its normal central position the valve plate 3| will be held against valve seat 32 to close the valve. If desired an auxiliary spring 4| may be employed for holding its seat. When the pressure within thegenerator A is lowered below atmospheric pressure, the pressure in chamber 38 above diaphragm 34 will be correspondingly lowered and the atmospheric pressure within chamber 36 beneath the diaphragm will lift the valve so as to permit gas to flow from pipe 29 to pipe l9 and thence to burner 2|. The greater the vacuum within the generator, the lower the pressure above diaphragm 34 and consequently the greater pressure differential will be exerted on this diaphragm to open the valve so mitted to burner 2| will be increased proportionately as the pressure is lowered within the generator. A very small pipe 6|, provided with a normally open stop-cock 62, is shunted around valve D to connect gas supply pipe 29 with gas pipe |9 so that a small flow of gas to the burner 2| will always be permitted, whereby a small pilot flame, insufiicient for normal heating purposes is maintained even though valve D is closed.

In operation, water flows into the generator A through pipe l2 and is discharged through outlet that the supply of gas adl3 into the pan 9. When the pan 9 is completely filled it overflows in the form of drops falling from the upper edge of the pan into the annular basin or reservoir 8, and in the form of a thin film flowing down the inclined walls ll of the pan. Any excess of water in reservoir 8 flows through openings 25 and down the inner surface of inner annular wall 6 into the reservoir l5. Any excess of water in reservoir l5 flows down through air tube l4 and out through pipe l6 and the discharge pipe 26 to the sewer.

Assuming that a partial vacuum exists within the generator A, valve D will be opened to admit fuel gas to the burner 2| and air will be drawn in through supply pipe IS on account of the lower pressure existing within the generator. The gas and combustion air will be ignited within combustion chamber 22 and through the surrounding walls will heat the water in receptacles 9, 8 and I5. The products of combustion pass out through the openings 24 and 25 and contact directly with the exposed surface of the water in the three containers and also with the water dropping from the pan 9 and with the thin films of water flowing down the outer surfaces of the containers 9 and 8. As the bodies of water in receptacles 9 and 8 are heated, the water will expand thus causing an overflow in contact with the rising products of combustion. The heating medium consisting of the mixed steam and passes out through supply pipe 4 to the radiating system. As the pressure is further lowered within generator A, the valve D will be further opened to admit a greater quantity of fuel gas and a proportionately greater will be drawn into pipe l6. This provides more rapid combustion and a larger flame 23, and consequently increases the rate of steam generation. When the pressure within generator A rises to atmospheric, valve D will be closed to cut off the supply of gas and no more combustion air will be drawn in through inlet pipe |6. The generator will therefore cease to function, although a small pilot flame will be maintained as hereinabove described. It will be noted that this pilot flame is substantially surrounded by the bodies of water always present in the generator so that a large portion of the heat from this pilot will be absorbed by the water. This minimizes the heat loss, and the pre-heated water present iii the generator expedites and facilitates the restarting of the normal generating process.

The heating medium passes from supply pipe 4 through risers 42 and inlet valves. 43 to the respective radiators or heat emitters B. While only two radiators B have been here shown by way of example it is to be understood that a greater number of radiators can be used. Each inlet valve 43 comprises the usual cutoff valve operated by handle 44, and a metering plate 45 provided with a central orifice 46 is interposed between the valve chamber and the inlet 41 leading to the radiator. The orifice 46 in plate 45 will be properly proportioned to meter the right proportion of heating medium to each radiator depending upon the size, volume and condensing capacity of the radiator. It will be understood that when valve 43 is closed no heating medium at all is admitted to the radiator, but when the valve is opened a restricted flow of heating medium is admitted to the radiator through the orifice plate.

One or more of the valves 43 may be provided with a small opening to permit the outflow of the products of combustion flow of combustion air products of combustion of the pilot-flame even 75 cally increasing the rate of generation -mand. The system is thus though tha valves are closed. This opening insures sumcient draft of air to supply the pilot flame but not suflicient to create a vacuum in the boiler that will operate the diaphragm valve D.

Discharge pipes 48 lead from the respective radiators B to an outlet main 49 leading up to the exhausting mechanism 0. This exhausting mechanism comprises a suitable fan or other suction device 50 driven by motor 5| and adapted to draw gases through main 49 and expel them through pipe 52 to the outer atmosphere. The motor 5| is supplied with power through leads 53 and controller 53', and may be manually thrown into or out of operation by the switch indicated diagrammatically at 54, or may be automatically thrown into and out of operation in accordance with changes in the temperature within the building or at predetermined times by means of thermostat 55.

The condensate formed within the radiators B flows out through pipes 48, 49 and I2 and thence back into pan 9 of generator A. An inlet pipe 56 from theoutside water supply and controlled by valve 57 leads into pipe l2 whereby the system may be properly filled with water or additional water in the generator due to water vapors formed in the combustion process, this excess being discharged through pipe 26 as already described.

When exhauster C is in operation it will draw gases through pipes 49 and 48 and create a vacuum in the radiators B. If one or more of the inlet valves 43 are opened, this suction will be pipes 42 and 4 to the generator A consequently lowering the pressure in the generator, opening the fuel valve D and drawing in combustion air through pipe I 6. The burner will heat the water within the generator producing steam which, together with the prodis drawn out as a heating medium through supply main 4 and risers 42 and admitted in properly metered proportion through orifice 46 to the radiator. The radiators B will be made comparatively large so that practically all of the steam will be condensed and give out its heat while within the radiators, and such heat as remains within the non-condensible combustion gases will also be utilized for heating purposes while within the radiators. The non-condensible gases are drawn out by the exhausting mechanism C through pipes 48 and 49 and expelled through pipe 52 to the outer air. The condensate formed within the radiators flows down through pipes the generator where it is reconverted into steam.

It will now be seen that if an additional inlet valve 43 is opened so as to throw an additional radiator B into service there will be an additional condensing space and an additional drain of heating medium through the supply pipe into this radiator thereby further lowering the pressure within generator A. As already described, this serves to admit an increased supply of fuel and combustion air to the generator thus automatiof t e heating medium to care for the increased depractically automatic, the rate of generation of the heating medium being varied in accordance with the number of radiators thrown into service by operationof the inlet valves 43.

48, 49 and I2 into It will now be apparent that the system can only be operated when sub-atmospheric pressures exist in the system, and the generation of the heating medium is controlled automatically by the changes in this sub-atmospheric pressure, which in turn are controlled by the changes in the volume of radiating space put into service.

The system is entirely closed from the atmosphere within the building, and if any leakage occurs it will be into the system due to the lower pressure existing therein, and there will be no escape of combustion gases into the rooms.

One of the principal objections to heating systems heretofore used which utilized the products of combustion as a heating medium has been the corrosive effect of these gases in the piping system and radiators. This corrosive action is largely caused by excess air in the system, when combustion air is supplied under pressure. Since this system operates under a vacuum, excess air is practically eliminated and corrosion is minimized. The inside of all metal parts may also be coated with a corrosion resistor, if desired.

This type of heating system is most efiicient since there is very little heat developed in the system that is not radiated or conducted into the building for heating purposes. Practically the only heat losses are in the non-condensible gases which are discharged by the exhausting mechanism C through pipe already given up most of their heat while in the radiating system and are at a much lower temperature than the gases ordinarily discharged through the chimney of an ordinary furnace. It will be noted that the excess water dis- 3 charged through pipe 26 passes out through the air inlet conduit l6 so as to heat the incoming combustion air and thus minimize the heat losses at this point.

It will be noted that this system utilizes only a. single pump which functions to maintain the circulation in the system, to exhaust the noncondensible gases from the system, and to supply the fuel and combustion air in proper proportions to the generator.

While a gas-burning furnace has here been shown by way of example, it will be apparent that a burner utilizing oil or solid fuel for combustion purposes could be substituted by making suitable changes in the form of generator and supply connections used.

This heating system is particularly adapted for use in small buildings where a simple and inexpensive system is desirable. This system utilizes a minimum number of parts, which are largely interchangeable, occupy little space, and are easfly controlled. It will be understood that the system here shown and described by way of example is merely illustrative, and many changes may be made in the form, number and proportions of the parts used without departing from the broad principles of this invention as set forth in the claims which follow.

We claim:

1. The method of heating consisting in admitting water, combustion air and fuel to an enclosed combustion space, burning the fuel in said space, and maintaining a sub-atmospheric pressure in a radiating space connected with the combustion space whereby the mixed fluid heating medium formed in the combustion space is drawn therefrom and into the radiating space, and a partialvacuum is created in the combustion space, increasing or decreasing governing 52, and these gases have the rate of fuel supply and the inflow of combustion air from the outer atmosphere in response to an increase or decrease respectively in the degree of vacuum in the combustion space, and varying the volume of the radiating space in which the heating medium is partially condensed and consequently varying the degree of vacuum in the combustion space.

2. The method of heating consisting in burning fuel in the presence of water and thus creating a mixed heating medium in a confined space forming one portion of a circulation system, the system embodying a plurality of spaces from which heat is emitted wherein the steam in the heating medium is condensed thus producing a partial vacuum in the system, exhausting the cooled non-condensable gases from the system, returning the condensate to the combustion space for re-conversion into steam, varying the number of heat emitting spaces in service and thereby varying the degree of partial vacuum thus created in the system, and automatically increasing or decreasing the quantity of heating medium produced in response to an increase or decrease respectively in the degree of vacuum thus produced.

3. The method of heating consisting in burning fuel in the presence of water and thus creat ing a mixed heating medium consisting of steam and products of combustion in a confined combustion space, circulating the heating medium through a radiating system comprising a plurality of condensing spaces, restricting the inflow of heating medium to each space in accordance with the condensing capacity of the space, condensing the steam in the condensing spaces and withdrawing cooled non-condensable gases from the system thereby maintaining a partial vacuum in the system, varying the number of condensing spaces in service thus varying the pressure in the combustion space, and automatically increasing or decreasing in accordance with a decrease or increase in pressure respectively in the: combustion space.

4. The method of heating consisting in generating a mixed heating ,medium consisting of steam and gaseous products of combustion in one portion of a closed circulation system, condensing the steam in a remote portion of the circulation system and exhausting the cooled non-condensable gases from the system and thereby creating a partial vacuum in the closed system and causing the circulation therein, and increasing or decreasing the inflow of combustion air and fuel to the generating space in response to an increase or decrease respectively in the degree of vacuum created in the system.

5. The method of heating consisting in generating a mixed heating medium consisting of steam and gaseous products of combustion in one portion of a closed circulation system, condensing the steam in a remote portion of the circulation system and exhausting the cooled noncondensable gases from the system and thereby creating a partial vacuum in the closed system and causing the circulation therein, increasing or decreasing the inflow of combustion air and fuel to the generating space in response to an increase or decrease respectively in the degree of vacuum created 'in the system, and automatically stopping the exhausting process and hence decreasing the vacuum when a predetermined maximum temperature is reached in the space being heated.

6. The method of heating consisting in generculation, and returning the rate of combustionating, by burning fuel in the presence of water, a mixed heating medium consisting of steam and gaseous products of combustion in one enclosed space of a circulation system, causing circulation of this heating medium to another portion of the system wherein the steam is condensed and the non-condensable gases give out some of their heat and exhausting the cooled gases from the system thereby creating a partial vacuum throughout the system and causing the cirthe condensate to the generating space, the combustion air being drawn into the generating space by the partial vacuum created in the system, and increasing or decreasing the rate of fuel supply in response to an increase or decrease respectively in the degree of vacuum in the generating spac.

'7. Method of heating which comprises: introducing water into a steam generating and mixing space; causing hot gases of combustion to pass through said space in contact with the water to generate the same into steam, passing the mixture of steam and combustion gases through a heat emitting space, maintaining sub-atmospheric pressure in both spaces by condensing the steam and withdrawing cooled non-condensable gases from said heat emitting space; and increasing or decreasing the rate of introduction of combustion gases to said generating space and starting or stopping the withdrawal of non-condensable gases from the heat emitting space in response to a predetermined decrease or increase respectively in temperature at a determined point.

8. The method of heating consisting in generating a heating medium in an enclosed generating space-under a sub-atmospheric pressure which is automatically lowered or raised respectively in response to an increase or decrease in the heat requirements in a space to be heated. the heating medium consisting of mixed steam and products of combustion, and circulating this heating medium through spaces in which the steam is condensed and from which the heat is emitted, the rate of production of the heating medium being regulated by changes in the controlled pressure in the generating space, a lowered pressure increasing the rate of generation and' an increased pressure decreasing this 5 rate.

' 9. The method of heating consisting in burning fuel in an enclosed generating space in the presence of water so as to generate a heating medium consisting of mixed steam and products of combustion,

automatically maintaining a sub- 5 atmospheric pressure in the generating space which pressure is raised or lowered respectively in response to a decrease or increase in the heat requirements in a space to be heated, andcirlculating the heating medium through spaces in which the steam is condensed and from which the heat is emitted, the rate of production of the heating medium being regulated by changes in the controlled pressure in the generating space, a. lowered pressure increasing the rate of generation and an increased pressure decreasing this rate.

10. The method of heating consisting inv generating in an enclosed generating space under a thermostatically controlled sub-atmospheric pressure a heating medium consisting of mixed steam and products of combustion, and circulating this medium through spaces in which' the steam is condensed and from which heat is emitted, the rate of production of the heating medium being regulated by changes in the con space, returning the condensate to the combustrolled pressure in the generating space, a. lowtion space, thermostatically controlling thesubpresence of water and under a thermostatically bustion space.

controlled sub-atmospheric pressure so as to gen- 14. The method of heating consisting in burnerate a heating medium consisting of mixed ing fuel in an enclosed generating space under a steam and products of combustion, and circucontrolled sub-atmospheric pressure in the pres- 1o lating the heating medium through spaces in ence of water so as to generate a heating medium hausting the cooled non-condensable gases from 15. The method of heating consisting in mainthe condensing space and thereby maintaining a taining a controlled sub-atmospheric pressure heating medium, and producing a suction for fuel in the combustion space and passing the hot :0

fuel in he presence of water in a closed relieved of a portion of their heat, exhausting V combustion space to p c P ial y Conthe cooled non-condensable gases from the condensable heating medium consisting of products densing spaces thereby maintaining the sub- 40 of Combustion and Steam, the combustion Space atmospheric pressure in the spaces and returning being connected with a condensing space into the ndensate to the mixing-space, and stopwhich the heating medium is introduced, exping or starting the exhausting process in re- Ila-listing t e co nomcondensflble 8 8 m sponse to temperature changes in the space heathe condensing Space d thereby maintaining ed by heat discharged from the condensing 45 controlled partial vacuum in the condensing and spaces,

combustion spaces, causing circulation of the CLAYTON A. D NHAM. heating medium, and producing a suction for AUBRA R. DUNHAM. drawing combustion air into the combustion CERTIFICATE OF CORRECTION.

Patent No. 2,046,813. July 7, 1956.

CLAYTON A. DUNHAM, ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 3, second column, line '75, claim 1, strike out the word "governing; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office. Signed and sealed this 8th day of September, A. D. 1936.

Leslie Frazer I Acting Commissioner of Patents. 

